P541: OUTCOMES AND MANAGEMENT OF PATIENTS WITH NEWLY DIAGNOSED ACUTE MYELOID LEUKEMIA PRESENTING WITH HYPERLEUKOCYTOSIS
Authors: F. Haddad, K. Sasaki, T. Abuasab, S. Venugopal, D. Rivera Delgado, A. Bazinet, R. Babakhanlou, K. Kim, J. Senapati, F. Ong, S. Desikan, N. Short, N. Pemmaraju, G. Borthakur, C. DiNardo, N. Daver, E. Jabbour, G. Garcia-Manero, F. Ravandi, T. Kadia
Journal: HemaSphere (2022)

Background: Patients with acute myeloid leukemia (AML) presenting with hyperleukocytosis have higher mortality rates and inferior outcomes. Analyzing the factors associated with mortality and survival in AML patients with a white blood cell count (WBC) ≥100 x 109/L can guide management and improve early mortality. Aims: To analyze the outcomes of patients with AML presenting with hyperleukocytosis and establish a treatment algorithm for the management of those patients. Methods: In a retrospective analysis, we screened patients who presented to our institution for newly diagnosed AML over the period of 10 years and identified those with WBC ≥100 x 109/L. Logistic regression models estimated odds ratios (OR) for 4-week mortality and Cox proportional hazard models estimated hazard ratios (HR) for overall survival (OS). Results: We identified 129 patients with newly diagnosed AML and hyperleukocytosis. Median age was 65 years (range, 23-86 years) and 66% of patients had ECOG performance status (PS) <2. Median WBC was 146 x 109/L (range, 100-687) and 78 patients had clinical leukostasis (CL) including renal failure in 31 patients (24%), new onset hypoxia in 29 patients (23%), headache in 19 patients (15%), chest pain in 9 patients (7%) and neurological symptoms in 3 patients (2%). FLT3 and RAS pathway mutations were found in 63% and 27% of patients, respectively. 29 of 129 patients (22%) had poor-risk cytogenetics. Compared with patients without evidence of CL, those with CL were less likely to have good PS (ECOG PS <2, 58% vs 82%; P = 0.006), had higher 4-week mortality (16% vs 2%; P = 0.015) and 8-week mortality (19% vs 6%; P = 0.038). Cytoreduction consisted of hydroxyurea in 124 patients (96%), cytarabine in 69 patients (54%) and leukapheresis in 31 patients (24%). Patients who underwent leukapheresis were less likely to receive cytarabine compared with those who did not (35% vs 59%; P = 0.024); and tended to have more CL compared with patients who did not (74% vs 56%; P = 0.093). 30 patients had tumor lysis syndrome (TLS). TLS risk did not increase with WBC and was not associated with the cytoreductive modality used. 11 patients had intracranial hemorrhage (ICH): 9 patients (82%) with WBC ≥150 x 109/L and 18% with WBC <150 x 109/L (P = 0.048). No association was observed between the incidence of ICH and the cytoreductive therapy. 4-week and 8-week mortality rates were 10% and 14%, respectively. After a median follow-up of 49.4 months (95% CI, 26.2-72.6), median OS was 14.3 months (95% CI, 7-21.6), with 2-year OS of 40%. Median OS was 12.3 months (95% CI, 7.4-17.2) compared with 29 months (95% CI, 2.1-55.6) in patients with or without CL, respectively (P = 0.007). Median OS was 9.9 months (95% CI, 7.5-12.2) and 21.3 months (95% CI, 10.7-31.8) among those who did or did not undergo leukapheresis, respectively (P=0.003). Median OS was 42 months (95% CI, 14.2-69.8) in patients younger than 65 years compared with 8 months (95% CI, 6-10) in those 65 years and older. Image:Summary/Conclusion: Older age, poor-risk cytogenetics, TLS and disseminated intravascular coagulation (DIC) were associated with early mortality and inferior OS in patients with hyperleukocytosis. Careful monitoring of those patients with prompt cytoreduction and management of complications may help improve their outcomes.